Gerry Neugebauer, an astrophysicist who pioneered ways to peer into previously invisible sectors of outer space, helping to discover hundreds of thousands of planets, stars and galaxies, died on Sept. 26 in Arizona. He was 82.

His death, at an assisted living facility near Tucson, was caused by complications of spinocerebellar ataxia, according to his wife, Marcia Neugebauer, a distinguished geophysicist known for her work on solar wind and comets.

Dr. Neugebauer (pronounced NOY-guh-bower) was a former chairman of the division of physics, mathematics and astronomy at the California Institute of Technology and director of the Palomar Observatory there.

And in the study of infrared radiation, a form of electromagnetic radiation, he was considered a father of the field, along with Frank J. Low of the University of Arizona.

Dr. Neugebauer’s biggest achievement was in detecting and interpreting infrared radiation emanating from outer space. Infrared radiation provides insights about the universe that radio waves or X-rays cannot.

A major advance came in 1983, when he was the scientific director of a satellite mission to collect heavenly data from infrared rays. For that project — the Infrared Astronomical Satellite, or IRAS, sponsored by NASA, Britain and the Netherlands — he helped develop instruments sensitive enough to detect a 20-watt light bulb on Pluto or a speck of dust from a mile away.

His team pinpointed more than a half-million sources of infrared radiation in the sky, many of them galaxies. It found rings of debris and dust around stars that were an early clue that planets exist beyond Earth’s solar system.

“Infrared at the time brought a whole new perspective on astronomy that people didn’t even know existed,” Eric Becklin, professor emeritus of experimental astrophysics at the University of California, Los Angeles, said in an interview on Wednesday.

Charles Beichman, executive director of the NASA Exoplanet Science Institute at Caltech, called the infrared advances over the past half century “a revolution in our understanding of solar system objects and material around stars.”

“Gerry was there at each step of opening a new window on the universe,” he said.

Thousands of research papers have been written using information gained from the IRAS mission. Using that data, scientists have learned that half of the energy released by galaxies is in the form of infrared emission, created when interstellar dust absorbs light from young stars and radiates it as heat.

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An artist’s rendering of the Infrared Astronomical Satellite, a mission for which Dr. Neugebauer was scientific director.CreditNASA/JPL-Caltech

The James Webb Space Telescope, which is to be launched into orbit in 2018, will detect only infrared radiation and is expected to vastly expand scientists’ knowledge of space.

IRAS found that the universe is far dustier than previously thought. But because it did not have to deal with the distorting effects of Earth’s atmosphere, it could penetrate the dust, using a telescope a million times more effective than earthbound ones, Dr. Beichman said.

Among the satellite’s discoveries were previously undetected galaxies 100 times brighter than Earth’s, said Thomas Soifer, the current chairman of physics, mathematics and astronomy at Caltech.

“Our imagination wasn’t nearly as good as what the universe produces,” Dr. Soifer said in an interview on Thursday.

Detecting heat in the utter cold of outer space was accomplished by making the telescope even colder. This was done by surrounding it with helium supercooled to a temperature of 2 degrees Kelvin, or minus 456 degrees Fahrenheit. The telescope could then detect objects emitting infinitesimal amounts of infrared radiation because it was colder than they were.

Gerhart Otto Neugebauer was born in Gottingen, Germany, on Sept. 3, 1932. The next year, his father, Otto, a celebrated historian of mathematical astronomy, refused to sign an oath of loyalty to Hitler, and the family moved to Copenhagen. In 1939, they had moved to Providence, R.I., where his father taught at Brown University.

Gerhart legally changed his name to Gerry (pronounced Gary) as a teenager. He graduated from Cornell with a degree in physics and earned a Ph.D. in physics from Caltech.

From 1960 to 1963, Dr. Neugebauer served in the Army, which assigned him to the Jet Propulsion Laboratory in California, a NASA facility managed by Caltech. There, he designed the infrared equipment for the Mariner 2 mission to Venus in 1962, the first robotic probe to make a successful planetary encounter, from as close as 22,000 miles. Caltech soon hired him for its physics faculty.

Early on he worked with Robert B. Leighton of Caltech, who in the early 1960s developed a telescope that Dr. Neugebauer used to sweep the sky from the Mount Wilson Observatory, northeast of Los Angeles. Many astronomers at first considered it a waste of time, Dr. Soifer said.

But working with Dr. Becklin, Dr. Neugebauer persisted and found an object the size of the solar system. It turned out to be a newborn star, a discovery that shed light on how stars are formed. He and his colleagues went on to locate the exact center of the Milky Way, the galaxy that holds Earth’s solar system.

Dr. Neugebauer was a member of the National Academy of Sciences, the American Philosophical Society and the American Academy of Arts and Sciences. He received the Space Science Award of the American Institute of Aeronautics and Astronautics, and the Herschel Medal of the Royal Astronomical Society in Britain, of which he was a member.

He moved to Tucson in 2002. Besides his wife, the former Marcia MacDonald, he is survived by his daughters, Carol Kaplan and Lee Neugebauer; and two granddaughters.

Dr. Neugebauer’s discovery of the Milky Way’s center prompted many scientific investigations, many by researchers he had helped mentor. One of them, Andrea Ghez, an astronomer at U.C.L.A., has provided persuasive evidence that at the galaxy’s center is a massive black hole.

Dr. Neugebauer all but predicted it decades ago. In 1983, after the success of IRAS, he said, “It is proven true that no one had ever opened a new region of space without getting remarkable results.”